musl - musl - an implementation of the standard library for Linux-based systems

musl - an implementation of the standard library for Linux-based systems

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author	Rich Felker <dalias@aerifal.cx>	2013年08月31日 01:12:00 -0400
committer	Rich Felker <dalias@aerifal.cx>	2013年08月31日 01:12:00 -0400
commit	7cc49f98a2b5346259d2209ba14d7c18959f9369 (patch)
tree	b51534ed3320b2621a59d4bd9d70b8a83ed8409f /src/signal/sigqueue.c
parent	d0f0fa484c5216710936715c176f67b3781e4b71 (diff)
download	musl-7cc49f98a2b5346259d2209ba14d7c18959f9369.tar.gz

fix breakage in synccall due to incorrect signal restoration in sigqueue

commit 07827d1a82fb33262f686eda959857f0d28cd8fa seems to have introduced this issue. sigqueue is called from the synccall core, at which time, even implementation-internal signals are blocked. however, pthread_sigmask removes the implementation-internal signals from the old mask before returning, so that a process which began life with them blocked will not be able to save a signal mask that has them blocked, possibly causing them to become re-blocked later. however, this was causing sigqueue to unblock the implementation-internal signals during synccall, leading to deadlock.

Diffstat (limited to 'src/signal/sigqueue.c')

-rw-r--r--

src/signal/sigqueue.c

1 files changed, 3 insertions, 2 deletions

diff --git a/src/signal/sigqueue.c b/src/signal/sigqueue.c
index bdb12856..eb4d184f 100644
--- a/src/signal/sigqueue.c
+++ b/src/signal/sigqueue.c

@@ -3,6 +3,7 @@

#include <unistd.h>

#include <stdint.h>

#include "syscall.h"

+#include "pthread_impl.h"

int sigqueue(pid_t pid, int sig, const union sigval value)

{

@@ -14,9 +15,9 @@ int sigqueue(pid_t pid, int sig, const union sigval value)

si.si_code = SI_QUEUE;

si.si_value = value;

si.si_uid = getuid();

- pthread_sigmask(SIG_BLOCK, (void *)(uint64_t[1]){-1}, &set);

+ __block_app_sigs(&set);

si.si_pid = getpid();

r = syscall(SYS_rt_sigqueueinfo, pid, sig, &si);

- pthread_sigmask(SIG_SETMASK, &set, 0);

+ __restore_sigs(&set);

return r;

}

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